The objective of this study was to evaluate the role of ultrasound (US)-guided core biopsy of highly suspicious breast lesions in decreasing the cost of establishing the diagnosis. There were 172 consecutive US-guided breast core biopsies performed during the calendar year 1994, 35 of which were malignant. These 35 women are the subject of this analysis. Patient charts were reviewed to determine the results of the core biopsies as well as the number of surgical procedures performed. The management of these patients was then contrasted with that of 38 patients diagnosed with infiltrating carcinoma via needle localization and open surgical biopsy during a similar time period. Twenty-nine of the 35 women had a single surgical procedure after the diagnosis of malignancy was made by US-guided core biopsy. Just 9 of the 38 patients in the needle localization (control) group had only one surgical procedure. The cost of establishing the diagnosis and treating patients with infiltrating carcinoma was substantially less for those diagnosed via US-guided biopsy. US-guided core biopsy of highly suspicious lesions reduces the number of subsequent surgical procedures in most women. The cost savings offer a significant advantage over conventional needle localization and surgical excision.

Stereotactic core biopsy of breast masses has been shown to be accurate in establishing a tissue diagnosis of mammographically detected lesions.1-6 Recently, one group presented data showing that stereotactic core biopsy of suspicious lesions significantly reduced the number of surgical procedures performed to manage the abnormalities.7 However, there are many institutions, such as our own, that do not have access to a stereotactic unit.

When a nodule is detected by mammography or is palpable, we perform ultrasound (US) of the relevant quadrant of the breast or of the palpable nodule. Since 1993, we have been using US to guide percutaneous needle core biopsy (NCB) of nodules that are visible sonographically and appear solid. This study was undertaken to examine the impact of this diagnostic procedure on the surgical therapy of patients with infiltrating carcinoma of the breast and to compare it with the management of a group of patients who underwent needle localization and open surgical biopsy. An analysis comparing the costs of each management also was undertaken.

Materials and methods

There were 172 US-guided 16-gauge NCBs performed between January 1, 1994 and December 31, 1994. Every patient had a sonographically solid lesion that had been detected by physical exam, screening mammography, or US. There were 137 benign lesions and 35 malignant lesions. The 137 benign lesions are part of an ongoing 24-month clinical follow-up study to determine the positive predictive value of the benign diagnosis.

The 35 malignant lesions are the subject of this review. The pathological diagnoses from the large NCBs in 33 of the 35 patients who underwent a surgical procedure were compared with the final pathological diagnoses from the lumpectomy or mastectomy specimens. In addition, all surgical procedures performed after the NCBs were reviewed. This study group of 35 patients with the diagnosis of malignancy by NCB was compared with a control group.

The control group was obtained from 62 consecutive patients diagnosed between March 1993 and December 1994 with an infiltrating carcinoma of the breast in the conventional fashion, via needle localization and open surgical biopsy. Twenty-three of the 62 patients were excluded, as the biopsy was performed for microcalcifications. An additional patient was excluded because only ductal carcinoma-in-situ was found. Thirty-eight of the 62 patients presented with a solid nodule on physical exam, screening mammography, or US and underwent x-ray needle localization and open surgical biopsy, which revealed infiltrating carcinoma. This route of diagnosis was chosen because of patient preference or the preference of the referring physician. This group of 38 patients with a solid mass and infiltrating carcinoma make up the comparison group.

Informed consent was obtained prior to the US-guided 16-gauge NCB. No laboratory studies were performed unless the patient had a significant history for possible coagulopathy. Aspirin use was specifically screened. The biopsy technique described previously by Parker et al was employed.8 The patient was placed in a supine oblique position with the breast elevated and the ipsilateral arm extended above the head. The lesion was identified and a mark with indelible ink was made just above the lesion.

A wide Betadine prep was then performed, centered on the mark. The transducer was wiped clean with alcohol; a sterile cover was not used, as it degrades visualization of the needle. Sterile gel was used as the coupling agent. A 7.5-MHz linear array transducer was used to localize the lesion in the center of the image. Local anesthesia was given into the skin immediately adjacent to the end of the transducer and was continued into the breast up to and around the lesion.

With the sonographer lining up the lesion and the skin puncture site, the 16-gauge biopsy needle was introduced and guided under continuous US visualization to the edge of the lesion. The biopsy gun was then fired, and US documenta

tion of the biopsy needle passing through the lesion was made. The needle was removed, and the material obtained was placed in 10% formalin (figure 1). A total of five passes were made into different areas of the lesion.9 Manual pressure was maintained by the sonographer between passes and by the patient for five minutes after the biopsy. The patient was instructed to avoid aspirin use for several days.

Results

Thirty-five patients had a diagnosis of malignancy of the breast established by US-guided 16-gauge needle core biopsy (table 1). There were 34 cases of infiltrating carcinoma and 1 case of lymphoma. All 35 cases had adequate tissue in the needle core biopsies to establish the diagnosis; no re-biopsies were necessary, and pathologic diagnoses were not equivocal.

Thirty-four of the 35 cases diagnosed as infiltrating carcinoma were confirmed in the subsequent resections (33 breast excisions, 1 pleural biopsy). There were two diagnoses of lobular carcinoma and one diagnosis of tubular carcinoma; all were confirmed in the larger resected specimens. Although lymphatic vascular invasion (LVI) was seen occasionally in the core biopsies, it was more common for LVI to be found in the resected specimen rather than in the core. The core biopsies adequately diagnosed infiltrating carcinoma; however, the amount of in-situ component, ductal or lobular, could not be evaluated in the cores. Extensive intraductal component (EIC), when present in the resected specimen, was not present in the cores.

The single case of lymphoma diagnosed by core biopsy was compared to a previous biopsy from another site in the patient. No additional breast tissue was removed. The histologic appearance of the lymphoma on the needle core biopsy was identical to an extramammary biopsy performed 12 years earlier.

Two of the 35 had no subsequent breast surgical procedure; the patient diagnosed with lymphoma was treated with radiation and chemotherapy; and one patient with a positive pleural biopsy was thought to have widely metastatic breast cancer and, thus, was not a surgical candidate. Twenty-nine of the 35 patients had a single surgical procedure following the US-guided 16-gauge needle core biopsy. Eleven of the 29 had mastectomies. Eighteen of the 29 had lumpectomies plus or minus axillary node dissection. Three of the 35 patients had 2 surgical procedures: initial excision followed by re-excision or mastectomy.

One of the 35 patients had 3 surgical procedures: excision, re-excision, and completion mastectomy.

Of the 35 US-guided 16-gauge needle core biopsies performed, there were no significant hematomas. (The only significant hematoma during the study period occurred in a patient taking high doses of aspirin for low back pain. The hematoma resolved completely without intervention. At follow-up exam, the lesion was re-biopsied and was found to be a fibroadenoma.) There were no infections, and there were no clinically significant complications that required medical or surgical intervention. This is similar to the very low incidence (6 out of 3,765) of clinically significant complications reported by Parker et al.1

Nine of the 38 patients in the control group had a single surgical procedure: the initial surgical biopsy. Five of the nine had indications for additional surgery, but this was not performed because of patient refusal (one out of five) or severe medical conditions that prevented further surgery (four out of five). Twenty-seven out of 38 patients had 2 surgical procedures (re-excision, mastectomy, plus or minus axillary node dissection). Two of the 38 patients had 3 surgical procedures (re-excision, mastectomy, plus or minus axillary

node dissection).

The cost of establishing the diagnosis of infiltrating carcinoma was much less in the US-guided 16-gauge needle core biopsy group than in the conventional needle localization and open surgical biopsy group (table 2). The total Medicare payment for the US-guided needle core biopsy was $661.98 in contrast to the total Medicare payment for needle localization and open surgical biopsy, which was $2,211.32. Thus, the US-guided NCB provides a 70% savings under the current Medicare fee structure. This actual savings corresponds closely to the savings estimated by Parker4 and Dowlatshahi.10

Discussion

The procedure of percutaneous breast biopsy, using either stereotactic or US guidance, has been demonstrated to be a reproducible and reliable alternative to surgical biopsy.1-6,11 The discussion now centers upon the question of which lesions to pursue with percutaneous biopsy. Some advocate that only indeterminate lesions be biopsied and not probably benign lesions that previously would undergo short-term follow-up.3 Franquet et al argue that aspiration of nonpalpable, probably benign lesions offers the advantages of immediately relieving patient anxiety and obviating the need for the patient to comply with mammographic follow-up.12 Disagreement also exists regarding the management of highly suspicious lesions.

Some authors state that they routinely do not perform core biopsies in patients with suspicious lesions, as "in most of these cases, our surgeons request that the lesions be excised to help in planning of therapy."5

Gisvold et al state that in their practice they recommend surgical excision for lesions if the likelihood of malignancy is high, as "core biopsy is considered an unnecessary expenditure of time and money."3 They do not explain how they arrived at this conclusion.

Liberman et al came to a different conclusion; they showed that stereotactic core biopsy of spiculated breast masses resulted in many fewer surgical procedures.7 However, they did not estimate cost savings for their patients.

Parker et al reported a series of patients with mammographically suspicious lesions who underwent stereotactic biopsies;6 they note that a few of their surgeons have "referred patients with nearly certain malignant lesions as determined mammographically for stereotactic gun biopsy so that they could proceed with definitive surgical treatment."

In our series, the US-guided 16-gauge NCB of suspicious lesions significantly changed the surgical management of the patients by decreasing the number of surgical procedures by 89%, with an attendant significant decrease in health care costs. Only 4 out of 35 patients in the US-guided NCB group required more than one trip to the operating room, whereas in the control group diagnosed by open surgical biopsy, 29 out of 38 patients required more than one trip to the operating room.

A very important consideration in the treatment of patients with breast carcinoma is the accuracy of the preoperative diagnosis, which can enable the surgeon to have a definitive preoperative discussion with the patient in order to achieve complete surgical management with a single operative procedure. There was 100% correlation between the pathological diagnoses of infiltrating carcinoma made on the US-guided NCBs and the final surgical resection specimens. Therefore, the positive predictive value of infiltrating carcinoma of the US-guided NCB was 100%. Parker et al had a similar positive predictive value of 100% for the diagnosis of carcinoma using 14-gauge US-guided NCBs.8

In this era of breast cancer treatment oriented towards breast conservation, complete removal of nonpalpable breast tumors with radiologic localization is aided by a definitive preoperative diagnosis of malignancy. In diagnostic localization biopsies, the surgeon tries to avoid significant cosmetic defect.

However, when one knows the lesion is malignant, the goal is to accomplish complete removal of the tumor with clear pathologic margins. This can be accomplished both by making a wider resection than is customarily done in a diagnostic biopsy, as well as by taking secondary tissue samples from the biopsy cavity with careful marking of location to document complete removal of the tumor pathologically.

Axillary lymph node dissection can then be done through a separate axillary incision or an en-bloc technique for those patients in whom an upper outer quadrantectomy is indicated. Because not all patients desire breast conservation, a definitive preoperative diagnosis enables those patients to proceed directly to mastectomy as a single operative event.

Since we began performing US-guided breast biopsies in 1993, our surgeons have supported enthusiastically the percutaneous biopsy of highly suspicious lesions. By making a histologic diagnosis of cancer with NCB, they can use the results to counsel the patient more accurately prior to definitive surgery, allowing for a more time-efficient discussion.

Prior to our performing NCBs of the suspicious lesion, the surgeon would have to schedule an appointment with the patient to discuss the long list of therapeutic options, dependent upon whether the lesion turned out to be malignant or benign, and then another appointment after obtaining the results of the open surgical biopsy to discuss therapy definitively. With the NCB results in hand, the initial office consultation is more focused and efficient, and the initial surgical intervention becomes a definitive therapy rather than a diagnostic test.

These data show that US-guided NCB is a safe, accurate, efficient, and less expensive method to diagnose a highly suspicious breast mass. The procedure of US-guided NCB had a 100% positive predictive value for the diagnosis of infiltrating carcinoma. It enabled 89% of patients to make a single trip, or less, to the operating room, and it provided these advantages at 30% of the cost of the conventional approach. AR

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The authors would like to thank Ruth McNeill for preparation of this manuscript.

References

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